1. Field of the Invention
This invention relates to a linear motion rolling guide unit equipped with a slider moved relative to a rail.
2. Description of the Related Art
In a linear motion rolling guide unit equipped with a slider moved relative to a rail, the application of a lubricant to the raceway faces of the rail makes the relative movement of the slider to the rail smooth.
Various methods by which the raceway faces are lubricated have been provided such as a method of lubricating the rolling elements rolling on the raceway faces or a method of directly lubricating the raceway faces. When the raceway faces are directly lubricated, a lubricating member disclosed in JP-H9-152095-A, for example, is employed.
The lubricating member is impregnated with a lubricant including oil and the like. A part of the lubricating member is secured to the slider in such a manner as to be in contact with the raceway faces. Therefore, when the slider slides on the raceway faces, the lubricant is supplied to the raceway faces of the rail from the lubricating member to lubricate the raceway faces.
As the raceway faces are thus lubricated, it goes without saying that the lubricant is gradually drained from the lubricating member, and eventually becomes incapable of lubricating the raceway faces. To avoid this, the above-described lubricating member is designed to be refilled with the lubricant later in order for the raceway faces to be lubricated for a long time. The structure of the lubricating member will be described below with reference to FIG. 8.
The lubricating member shown in FIG. 8 includes a body 101 impregnated with a lubricant including oil and the like. The body 101 has a top face 102 on which a pair or recessed portions 103 have open ends. The recessed portions 103 have a depth ranging from the top face 102 to the approximate midway-level of the body 101. A liquid lubricant 104 such as oil is stored in the recessed portions 103.
When the lubricating member, together with the slider, slides on the rail, the lubricant pre-immersed in the texture of the body 101 seeps gradually onto the raceway faces. While the raceways faces are thus lubricated by the seeping lubricant, the liquid lubricant 104 stored in the recessed portions 103 gradually spreads into the spaces between the molecular bonds in the body 101.
After the liquid lubricant has been absorbed by the body 101, an additional liquid lubricant 104 is fed into the recessed portion 103 from the top face 102 of the body 101. As a result, the lubricant can lubricate the raceway faces for a long time without being exhausted from the body 101.
In the aforementioned lubricating member, the recessed portions 103 for storing the liquid lubricant 104 have open ends formed in the top face 102 of the body 101. Such a conventional lubricating member having recessed portions 103 with open ends formed in the top face 102 can be employed only when the top face 102 is located in the upper area as shown in FIG. 8.
Specifically, if the recessed portions 103 are not located with their open ends facing upward, the liquid lubricant 104 will spill out from the recessed portions 103. For this reason, such a lubricating member is employed only in a slider sliding on the rail laid in the horizontal position, and cannot be employed in a slider sliding on a rail laid on a wall or a ceiling.
As so described, a conventional lubricating member has the problem of severely limiting the types of linear motion rolling guide units capable of using the lubricating member.
The conventional lubricating member has the recessed portions 103 refilled with the liquid lubricant 104. When the liquid lubricant 104 is directly supplied in the recessed portions 103, the liquid lubricant 104 is absorbed extremely quickly in a large amount by the body 101.
Such absorption of the liquid lubricant 104 into the body 101 causes over-impregnation of the body 101 with the lubricant. As a result, more than necessary amount of lubricant is fed onto the raceway faces, so that the lubricant is consumed more quickly. This gives rise to the impossibility of moderately lubricating the raceway faces over a long period.